I did something similar when racing motocross 5 years ago. Not much you can do for it. They will x-ray and make sure it doesn't have any fractures and that it isn't posteriorly dislocated (which is a much bigger issue). You may have also torn your subclavius muscle. I tore mine- it burned at the SC joint for abouy 4 months when I'd raise my arm above 90*. But it heals on its own. Look into ginger, turmeric, arnica, and vitamin C to help inflammation and healing.